It must be nice to be so wealthy that you don't actually know how rich you really are.Autonomy founder and chief executive Mike Lynch has done very well by selling his Cambridge-based internet security company to America's mighty Hewlett-Packard for £7 billion.As a result of the deal, he trousers £500 million and gets to keep a job with HP. Embarrassing then that advisers to the deal had to reveal that Lynch - rather than owning 19,808,546 Autonomy shares, as was claimed when the bid was launched, actually owns 19,798,546 shares. So, what's a mere 10,000 shares between friends? Well, at the bid price of 2550p a share, it's just over a quarter of a million quid. The kind of small change that slips down the back of the sofa